A picture image input method includes inputting a picture image of an object as a picture image signal. A histogram of a frequency with respect to brightness information of the picture image signal is created. A first brightness is created, which is a maximum brightness value within a region not greater than a first frequency value on a low brightness side of a brightness value which is lower by the a preset amount than the maximum brightness value within the histogram. A brightness group on a low brightness side of the first brightness side in the histogram is detected. A substantially maximum brightness value in the brightness group is set as a highlight point of the object. A gradation conversion table is created, which converts gradations of the picture image signal on the basis of the highlight point.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A picture image input method, comprising: inputting a picture image of an object as a picture image signal; creating a histogram of a frequency with respect to brightness information of the picture image signal; detecting a first brightness which is a maximum brightness value within a region not greater than a first frequency value on a low brightness side of a brightness value which is lower by a preset amount than the maximum brightness value within the histogram; detecting a brightness group on a low brightness side of the first brightness in the histogram; setting a substantially maximum brightness value in the brightness group as a highlight point of the object; and creating a gradation conversion table which converts gradations of the picture image signal on the basis of the highlight point.
2. The picture image input method according to claim 1 , further including: detecting a second brightness value which is a maximum brightness value in a range of a second frequency value or greater on the low brightness side of the first brightness; and detecting a third brightness value which is a minimum brightness value in the range of a third frequency value or less on a high brightness side of the second brightness; wherein brightness values not greater than the third brightness value constitute the values of the brightness group.
3. The picture image input method according to claim 2 , wherein: the third brightness value is set as the highlight point.
4. The picture image input method according to claim 1 , further including: inputting a second picture image of an object as a second picture image signal; and converting gradations of the second picture image signal by the gradation conversion table.
5. The picture image input method according to claim 1 , wherein: the gradation conversion table is a positive picture image gradation conversion table which outputs a maximum value with respect to the input value of the highlight point.
6. The picture image input method, according to claim 1 , wherein: the gradation conversion table is a negative picture image gradation conversion table which outputs a minimum value with respect to the input value of the highlight point.
7. A picture image input apparatus, comprising: means for inputting a picture image of an object as a picture image signal; means for creating a histogram of a frequency with respect to brightness information of the picture image signal; means for detecting a first brightness which is a maximum brightness value within a region not greater than a first frequency value on a low brightness side of a brightness value which is lower by a preset amount than the maximum brightness value within the histogram; means for detecting a brightness group on a low brightness side of the first brightness in the histogram; means for setting a substantially maximum brightness value in the brightness group as a highlight point of the object; and a processor which creates a gradation conversion table which converts gradations of the picture image signal on the basis of the highlight point.
8. The picture image input apparatus according to claim 7 , further including: means for detecting a second brightness value which is a maximum brightness value in a range of a second frequency value or greater on the low brightness side of the first brightness; and means for detecting a third brightness value which is a minimum brightness value in the range of a third frequency value or less on a high brightness side of the second brightness; wherein brightness values not greater than the third brightness value constitute the values of the brightness group.
9. The picture image input apparatus according to claim 8 , wherein: the third brightness value is set as the highlight point.
10. The picture image input apparatus according to claim 7 , further including: means for inputting a second picture image of an object as a second picture image signal; and means for converting gradations for the second picture image signal by the gradation conversion table.
11. The picture image input apparatus according to claim 7 , wherein: the gradation conversion table is a positive picture image gradation conversion tale which outputs a maximum value with respect to the input value of the highlight point.
12. The picture image input apparatus according to claim 7 , wherein: the gradation conversion table is a negative picture image gradation conversion table which outputs a minimum value with respect to the input value of the highlight point.
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March 24, 2004
April 15, 2008
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